Over the past three centuries, wheelchairs have been used by individuals whose legs are not capable of functioning normally or are absent. Many of these individuals are otherwise active and healthy members of society. However, due to their nonfunctioning, or absent legs, they are not able to participate in activities that require locomotion by use of the legs.
Beyond the common wheelchair, there has opened up in recent years a category of human-powered vehicles for handicapped riders, developed around wheelchair sports applications. Two styles have emerged: one is a variation on the conventional wheelchair, in which the rider pushes with the hands directly onto rings attached to the main wheels; and the other, typically referred to as a “handcycle”, derives from the bicycle, but with additional wheels, and the driving pedals moved to within reach of the hands. There are a number of disadvantages to both of these styles which render them unsuitable for either daily outdoor transportation, or for casual, recreational use, in the way that an able-bodied person might use an ordinary bicycle. Neither style is particularly well suited to the human form in terms of the ergonomic factors of efficient muscle use, strain avoidance, and overall rider comfort. By and large, they are adaptations of designs which have been optimized over time, for other purposes, or other muscle groups. Therefore, it is desirable to provide a wheelchair that overcomes the shortcomings of the prior art.